Automatic recording tube calipers for inside measurements within cylinders



Oct. 16, 1951 POOLE 2,571,161

AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 23, 1946 lo Sheets-Sheet 1 Oct. 16, 1951 F. M. POOLE AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS l0 Sheets-Sheet 2 Filed Feb. 23, 1946 l A l .2 LIZ-.1.

1951 F. M. POOLE 2,571,161

AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 25, 1946 10 Sheets-Sheet s FIGS.

23 e3 34 1 FIG I6.

Oct. 16, 1951 F. M. POOLE AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS 1O Sheets-Sheet 4 Filed Feb. 23, 1946 w w %m% mwk Q Q Q 0 Q id Q @v m VOE Oct. 16, 1951 F POOLE 2,571,161

AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 25, 1946 10 Sheets-Sheet 5 F. M. POOLE 6 AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS l0 Sheets-Sheet 6 Oct. 16, 1951 Filed Feb. 23, 1946 Oct. 16, 1951 POOLE 2,571,161

AUTOMATIC RECORDING TUBE CALIPERS FOR I INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 25, 1946 10 Sheets-Sheet 7 J A a m H Mg J FE M M u 4 u a 3 5 F kw H mg @m N N QN w 7 v u 5 w wMiwH fi 3 EM 5 w ma NM g g mv QM N 1951 F. M. POOLE AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS l0 Sheets-Sheet 8 Filed Feb 25, 1946 -q l I.

2 /5,i-1, z lfid 2 F. M. POOLE AUTOMATIC RECORDING TUBE CALIPERS FOR Oct. 16, 1951 INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 25 1946 10 Sheets-Sheet 9 En m ON OE Oct. 16, 1951 2,571,161

1 F. M. POOLE AUTOMATIC RECORDING TUBE CALIPERS FOR INSIDE MEASUREMENTS WITHIN CYLINDERS Filed Feb. 25, 1946 10 Sheets-Sheet 1o FIGZZ.

L L 3% L L KL. z 2a4 g, 5123 20/ 3 4 222 23 6a 243 I 2 26 2 V I I 237 7 23/84 e24 304 y I Z! 24 TFIGZI AMPLIFIER Patented Oct. 16, 1951 AUTOMATIC RECORDING TUBE 'oALr'PERs FOR INSIDE MEASUREMENTS WITHIN CYLINDERS Foster M. Poole, Dallas, Teiz.

Application February 23, 1946, Serial N 0. 649,650

20 Claims.

This invention relates to measuring instruments, and with regard to certain more specific features, to automatic recording tube calipers for inside measurements within cylinders.

Among the several objects of the invention may be noted the provision of a measuring instrument in the form of an inspection fixture for conventiently and quickly determining, indicating and registering inside sizes in automotive cylinders and the like; the provision of a measuring instrument of the calss described arranged for gang operation whereby an entire group of cylinders in a given engine block or the like may be inspected simultaneously; the provision of apparatus -of the class described in which the measurements taken during an operation are visibly continuously indicated and limits of deviation shown; the provision of apparatus of this class in which symbols coordinated with deviations are physically recorded on the engine block or the like being measured; the provision of apparatus of this class which provides diametr-al measurements at given axial points in the cylinders and also measurements of taper, both of said measurements being obtainable in two perpendicular planes; and the provision of apparatus of the class described which may be simply, conveniently and speedily operated. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the followin claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a front elevation of the apparatus, parts being broken away;

Fig. 2 is a right-side elevation of Fig. 1, parts being broken away;

Fig. 3 is a fragmentary section taken on line 33 of Fig. 1 but showing an alternative position of parts;

Fig. 4 is a horizontal section taken on line 4-4 of Fig. 1;

Fig. 5 is a horizontal section taken on line 5-5 of Fig. 1;

Fig. 6 is an enlarged detail section taken on line 66 of Fig. 4;

Fig. 7 is an enlarged longitudinal section of a transmitter, being taken on line 1-1 of Fig. 3;

Fig. 8 is an enlarged detail section taken on line 88 of Fig. 2;

Fig. 9 is a horizontal section taken on line 9-9 of Fig. 7;

Fig. 10 is a detail section taken along lines Hllil of Fig. 1 and of Fig. 11 and showing-a recorder;

Fig. 11 is a vertical section taken on line I l--l l of Fig. 10; I

Fig. 12 is a fragmentary front elevation of a single recorder dial; r

Fig. 13 is a view similar to Fig. 12 showing a moved position of certain parts;

Fig. 14 is an enlarged elevation of a recorder, being viewed from line l4-|4 of Fig. 1;

Fig. 15 is an enlarged'horizontal section taken on line I5l5 of Fig. 11, parts being broken away for condensation of the view;

Fig. 16 is a plan view of a recorder unit, being taken on line l6l6 of Fig. 11, parts being broken away;

Fig. 1'7 is an enlarged vertical section taken on line 11-41 of Fig. 1;

Fig. 18 is a front elevation of Fig. 17, parts being broken away to show details;

Fig. 19 is a horizontal section taken on lin Similar reference characters indicate corresponding parts throughout the several views 0 the drawings.

In my United States Patent 2,348,643, dated May 9, 1944, is disclosed in Fig. 1 a measuring transmitter instrument for internal calipering of a cylinder. Several similar transmitters are used in the present invention, operatin in parallel in multi-cylinder engine blocks. As may be seen from the patent and below, each transmitter which is indexed R herein consists broadly in a cylindric body adapted to be introduced loosely into the cylinder to be measured. The transmitter cylinder carries radially moving balls which traverse the inside of the cylinder to be measured, the balls being pressed outward by means of a pneumatically biased cone. The cone controls the position of a first armature which is operative in a coil having two sections which are electrically bridged with two sections in a receiver coil in a recording meter. The coil sections in the recording meter control a second armature which in turn controls the meter according to the amount of unbalance introduced into the circuit by motion of the first armature. Thus inequalities in the surface of the cylinder are visually registered by moving the balls through the cylinder to be measured. The present invention employs transmitters of this class in a way such as quickly visually to produce measurements and to register them fora group of cylinders, for example in eight cylinders of 3 an eight-cylinder engine block. Thus such blocks may be quickly inspected for reliable quantity production.

Referring now more particularly to Figs. 1-3, there is shown at numeral l a foundation carrying a fixed bed 3 which supports a vessel 5, the latter forming a liquid sump. This vessel is closed at the bottom by means of the head '1. Within the vessel 5 is a cylinder 9 which is also closed at the bottom by said head .1. This cylinder 9 carries an elevating piston H on the upper end of which is carried a hollow air-tight platen l3. Extending upward from the bed 3 are four posts, two diagonal ones of which are numbered l5 and the other two diagonal ones of which are numbered ll. The diagonally opposite posts |5 act as guides through bearings l9 formed at opposite corners of the platen l3. The posts I! do not pass through bearings in platen |3 but are free from it.

All of the posts l5 and I! support a stationary fixture 2| in the top surface of which are located supporting roller bearings 22. This fixture 2| carries longitudinal guide means 23 and a manually rotary end stop 25 for predeterminately positioning on the rollers 22 an engine block 21 to be tested. The stop 25 may at will be rotated counterclockwise (Fig. 2) to pass a block that has been tested (see also the dotted position of 25 in Fig. 5).

I The block 21 under consideration has several bored cylinders 29 (eight in the present example) which are to be checked for diameter size, roundness and taper. For this purpose the guides 23 and stop 25 are arranged to position the respective center lines of the cylinders substantially on the respective center lines of openings 3| in the fixture 2| (see Figs. 2, 3, 5 and 8). The spacings of the center lines of the cylinders 29 and those of the openings 3| are about the same, within tolerable limits, so that respective pairs of said openings 29 and 3| are in substantial alignment. The openings 3| are provided near their lower ends with hard steel or similar circular master gage rings 33, the inside diameters of which are of the proper sizes intended for the diameters of the cylinders 29. Above the master gage rings 33 are hardened steel guide sleeves 34 for purposes which will appear. These have inside diameters about equal to those of the respective gage rings 33. Gage rings 33 have oppositely disposed collars 36 and 38 which overlap where tangent as shown in Figs. 5 and 8. As indicated in Fig. 3, which is a section ata right angle to Fig. 8, there is only one gage ring per opening, rings of alternate openings having the alternate collars shown in Fig. 8. Coaxial with the openings 3| are the cylindric transmit.- ters R which are of thegeneral type described in said patent, and more particularly of an improved form such as shown in Figs. 7-9 herein.

Referring to Figs. 7-9, each transmitter R consists in an air-tight cylinder 35 attached to a hollow holder 31 by means of three posts, one of which is hollow as shownat 39 in Fig. '7. Each holder carries a flange 4| which is received in an opening 43 on the top of the hollow platen |3 (see Figs. 1 and 7). Packing is used to make an air-tight connection as shown at 45. Each holder 31 is held upright by means of a holding ring 2 fastened to the top of the platen I3. Each is rotary in the top of the hollow platen l3.

At the lower end of the air-tight cylinder 35 is a head 41 in which is a threaded adjustingmember 49. Member 49 backs a thrust bearing 5|.

4 The upper end of the cylinder 35 carries a head 53 from which extendsa fixed tube 55, the latter passing through the bearing 5| and member 49 into fixed engagement with the holder 31. A spring 57 forces an electromagnetic coil consisting of two sections 59 into engagement with the bearing 5|. This provides for a zero adjustment of the coil relatively to a slidable magnetic armature 5| in the fixed tube 55'. The armature 6| is normally biased by a tension spring 63 in the tube 55. The spring is anchored in the holder 3'! by 'a'pin 4. The armature 6|, by means of a fastening 65, i coupled to a nonmagnetic stem 61, the upper end of which carries a fiat disc 59. Below the disc is a bumper spring 5. Beyond the disc is located a hard, accurately tapered cone H which is held prisoner to the disc by means of a fastener 13. Fastener 13 has a head 8 under which is held an inner shoulder ID of the cone. The cone may move laterally on disc 69 but not endwise relatively thereto, although it may move endwise therewith. The cone may also rotate relatively to the disc. A thrust bearing 11 is located between the cone and the disc 69.

Bearing radially against the cone II are members of a pair of oppositely located balls 8|. These are held prisoner by means of threaded bushings 83. It will be clear that the radial positions of the balls'8| are determined by the axial position of the cone 1|. Lateral holding of the cone 7| is determined by small balls 85, which are held in bushings 8'! closed by means of threaded plugs'89. Additional balls 9| in bushings 93 are biased toward the conell by springs |2,' thus tending'to hold the cone with its median plane'in the median plane of the balls 8|. The stated coplanar relationship is indicated by the dotted line M- P 'of'Fig; 9. This is an important improvement in transmittersof this class. In previous'two point measuring devices of this type, such coplanar relationship was not maintained. In the present case, once the proper adjustment of the plugs 89 has been made for the purpose, the median plane MP o'f'the cone 7| remains the diametral plane common to the balls 8|, irrespective of the longitudinal or rotary movements of the cone. Stated otherwise, the cone 1! is cradled bythe' balls in the proper median position and it is resiliently held in its cradled position by means of the resiliently mounted balls 8|. It will be noted that the bushings 83, 8? and 93 are located ina head-95 held on member 53. At the end of this extension 95 is a guiding nose 91.

As will be seen later, each transmitter R accomplishes its measurements by a downward movement of the balls 8| through a cylinder 29. Thus th balls 8| will tend to rotate in the direction shown by the arrows in Fig. 8 which is a direction tending to move the cone downward in Fig. *8. This tendency is overcome by the pressure effect of the air in the tube 55 tending to extrude the stem 61 from said tube. This tends to press the disc 69 and to keep the cone H snugly against the balls while expandin the latter into contact with the cylinder that is to be measured. Air is brought into the tube 55 from'the holder-31. The holder 3 is in communication with compressed air inside of the hollow platen I3. The communication is through openings M of a-bushing l6. A wire cable'lflfi enters the bushing from the inside of the platen 3 This cable I96 passes to t he coil 59 via the hollow post 39. The cable, with the others servvertically on the pivots I 22 (Figs. 4 and 6).

ing' the transmitters, passes out of the platen I3 through an airtight joint, as indicated at I8 in Fig.- 3. Compressed air is fed to the inside of the:

platen I3 via com1ection'20.

From the above it will be seen that the traverse of a set of opposite balls 8I down a cylinder 29 will give diametral readings in a, given plane. In order that diametral readings in a plane at 90 may be obtained, the transmitters R have been made rotary in the top of the platen I3, the fianges 4I being rotary under packings 45. In order to rotate the transmitters simultaneously, each holder 3'I is provided with a lever I 0i which at its outer end is mechanically coupled with a translation coupler bar I09, the latter havin a pivoted handle III. When the handle III is thrown sidewise a predetermined distance, it will rotate all transmitters R through 90 (note the dotted lines in Fig. 4).

In either 90 position of every transmitter R it is desirable that it b oscillated through a slight angle as it traverses a cylinder so as to prevent undue localized wear on the respective balls 8!. To accomplish this the handle III is formed as a T, the head I24 of which swings The head I24 of the T carries openings I26 and I28 which are in effect alternate followers for a horizontally rotary cam I30. This cam lies above the upper surface of the platen I3. The cam is mounted on a cam shaft I32 which passes through an opening I34 in said upper surface. This opening is suitably packed to prevent air leakage. The shaft I32 is driven by a motor I38 and a gear reduction box I40. Thus in either of the 90 positions of the transmitters R, they are slightly rocked on vertical axes due to the driving action of the cam I30. The driving action is delivered to the transmitters R through the bar I24, pivots I22, bar I09 and levers I01. As indicated by the dotted lines in Fig. 4, the rocking action is effective in either position of the handle III. It will be understood that preliminary to moving the handle III it is always raised so as to clear the cam I30, but at the end of an adjustment the handle is always again lowered so as to place the cam I30 into a, respective one of the openings 26 or I28. The cam is arranged to shift the transmitters R through 4 in an interval of five seconds.

It will also be noted in connection with Fig. 4 that the end of the coupler bar I09 in one position of the transmitters R contacts a bar 42 of a gan of switches. These will be referred to later. 7

In their lowermost positions the transmitters R are as indicated in Figs. 1 and 2. In such positions the balls 8| are against the hard steel gage rings 33 in the fixture 2| (see Fig. 8). These rings 33 are of such size that the balls 8| take up a position providin a zero reference, as will later appear.

Supported by means of posts I2I on the bed 3 is a platform I25 which carries a case I21 in which are spaced dial openings I29. Openings I29 carry zero index reference marks I3I. Behind each opening is an indicating unit of the type shown in Figs. 10-16. There are as many indicating units as cylinders to be tested, eight in the present example. Each unit has exposed behind the respective opening I29 a part of the periphery of a dial drum I33 which carries plus and minus index marks starting at the nominal cylinder size. Each dial drum I33 is rotary with a shaft I35 being pinned at 44. Shaft I35 is carancing motor I4I.

6 ried onbearings 46 located in an individual compartment- 48 which is removable from the rear of the case I2I. Each dial is driven by a gear I3'I attached to shaft I35. Gear I3! is driven through.

a gear train I39 leading from a two-phase bal- The motor MI is connected into the circuit illustrated in Fig. 21 wherein I43 indicates an A. C. supply line. This supply line I43, through a transformer I45 and leads I41, supplies an impedance bridge circuit including coil sections 59 and I52 and leads I48, I49 and I50. These leads are connected across said coil sections 59 of the transmitter R and across corresponding sections I52 of a coil I'5I. The armature 6| of the transmitter R is shown in Fig. 21..

A corresponding armature I53 is associated with the sections I52 of coil I5I. 21, the center tap I60 on each pair of coil sections 59 and I52 supplies an input transformer I55 via line I49. This input transformer I55 feeds an amplifier I5'I which through leads I59 feeds one phase of the motor MI. The other phase of the motor is fed from the A. C. line I43 via leads I6I.

Connected with the gear I31 on the shaft I35 is a pinion I63 which is meshed with a sector gear I65 swinging on a pivot I61. This sector gear I65 carries an arcuate shoe I69 over which is wrapped and connected a flexible band III such as a flexible steel ribbon. This ribbon is connected with the armature I53. The latter is biased by suitable means such as a spring I0.

Thus each motor E4I controls the position of its associated dial I33. When the feeler balls 6| are held in a predetermined position for proper diameter, as in the gage rings 33, the armature I53 may be considered to be in a position to bridge circuit so as to energize the input side ofthe transformer I55. Any small unbalance is amplified in the amplifier I51 and applied to leads I59 to one phase of the motor I4I, the other phase of the motor being energized over connection I6I. Thus the motor MI is caused to reposition the armature I53 to establish a new balance of the impedance bridge circuit. A low A. C. voltage arising from any minute unbalancing of the bridge is amplified sufficiently to energize the balancing motor. The phase of this A. C. voltage is dependent upon the direction of the movement of thearmature 6| to reestablish balance of the impedance bridge. The proper direction and amount of movement of armature I53 will reestablish balance of the impedance bridge circuit.

The balancing motor I4I is a reversible variable speed induction motor, one winding of which is continuously energized by line voltage and the other energized by the amplified alternating voltage whose phase with respect to the line voltage determines the direction of rotation of the motor. Thus the phase is in effect recognized by the balancing motor I4 I', hence determining its direction of rotation. It is to be understood that any twophase motor will remain stationary when one of its phases is deenergized. Therefore wheneverv there is no energization of the connection I59 the motor I4I "will be stationary. The result is that the motor action follows the measuring actionqf As indicated in Fig.

the balls 8I, in one direction for plusdeviation:

from nominal diameter and. in the" reverse direction for minus deviation from nominal diameter. After each following action and balancing of the impedance bridge circuit, the dial drum I33 takes up a new position proportionately following the deviations from nominal. diameter.

A'dishedspring disc I8I serves to maintain coplanar the thin sector gear I65 and the pinion gear I83.

On opposite sides of the drum I33 are stationary gudgeons I83 and I85'which are respectively fastened to the sides of the compartment 48. Referring to the gudgeon I83, it carries rotary hubs I81 and I89 upon which are, respectively, pointers I9I and I93. The pointers I9I and I93 pass out through the opening I92 and carry radially adjacent fingers I95 and I91, respectively, next to the face of the dial I33 The pointers I9I and I93 are offset as shown at I99 in Fig. 10 to provide an eye for receiving the end of an armature pin 200, when this pin is in the position shown in Fig. 16. The pointer I93 goes under the pin and the pointer I9I over it. Since the hubs I81 and I89, are freely rotary on the gudgeon I83, pointers I9I and I93 will be moved by means of the pin 200 as the latter is moved with the drum I33. In order that the pointer I 93 may be biased against the bottom of: the pin 200, a weight 203 is provided to the rear of its hub I89. The pointer I9I is biased by its own weight against the top of the pin 200.

The purpose of the pointers I9I and I93 is to obtain maximum and minimum readings, as indicatedin Fig. 13. In order to have the pointers HI and I93 remain in moved positions of the same, a magnetic clutch is provided consisting of a stationary armature 205 on the gudgeon I83. In this clutch is a toric coil 201. U-shaped springs 209 normally bia apart the hubs I81 and I89. These hubs I81 and I89 are magnetic. Hence when the coil 201 is energized, the hubs will be drawn into light frictional engagement with the springs 209. Therefore if and when either pointer I9I or I93 is positioned by the rotary action of the drum I33 and pin 200, the respective pointer will maintain the maximum angular deflection to which it may be pushed in a given operation. Thus the pointers become maximum or minimum reading devices, whereas the dial drum I33 is a continuously reading device. Whenever the coil 201 is deenergized, the hubs I81 and I39 are pushed apart by springs 209 and-become released from friction and fall back into their positions against the pin 200. The-springs 209 are not absolutely necessary in all designs of the apparatus, since magnetic clutches may be made to open without springs of this type.

On the other side of the drum I33 and on gudgeon I85 are similar pointers 2H and 2I3, the latter being counterweighted, as indicated at 2I5. The pointers 2H and 2I3 carry fingers 2I1 and 2I9, respectively. They are also bent to form between them an eye 22I for accommodating the opposite end 223 of the pin 200 when the latter is moved to the left from the position shown in Fig. 16. The portion of the eye formed by'the pointer 2 I3 goes beneath the pin and that formed by the pointer 2 goes above the pin whenthe pin is moved. On the gudgeon I85 is a stationary clutch member 225 having a toric coil.221 mag netically operative upon the magnetic hubs 229 and 23I, respectively, of the pointers 2 I I and 2 I3. Spring clips 233 serve to bias apart the'ihubs 229- 8. and 23I. Energization of the coil 221 will draw together the magnetic hubs so as to provide light frictional clutch engagement to hold the pointers 2 II and-2 I3 at maximum deflections. When re-' leased, the pointers 2H and 2I3 will gravitate against the end 223 of the pin 200, provided the pin is in a position to the left of that shown in Fig. 16. As above mentioned in connection with springs 209, the springs 233 may be omitted.

Referring to Fig. 16, it is to be understood that the pin 200 when in the position shown will aifect the pointers I9I and I93 for maximum readings by said pointers. When the pin is in its alternative position to the left, its end 223 is inserted into the eye MI and its other end is withdrawn from the eye between the pointers I9I and I93. A solenoid coil 65 carried on the drum I33 serves to control the position of pin 200, the pin being movable through the center of the coil. Normally the pin 200 is biased to the operative position in connection with pointers I9I and I93, as shown in Fig. 16. This is when coil 66 is deenergized. This is due to return spring 68.

Each drum I33 carries a brush contact I15 which sweeps a commutator I11. The purpose of this is to set up electrical conditions for indexing a punch dial unit 50. There are as many dial units 50 as there are cylinders, namely, eight in the present example. These units are carried upon a shelf 52 extending over a pan rail 54 of the engine block being tested.

In each unit 50 (Figs. 17-19) is a rotary punch dial I82 around the periphery of which are vertically sliding punches I80, each being biased -.upward into a retracted position by a spring 56 (Fig. 17). Each punch carries on its lower face a suitable mark or symbol to be made on the pan rail 54 of the engine block 21. The symbols on the punches correspond to off dimensions, as indicated on the corresponding dial I33. Considering, for example, the four symbols on each side of the nominal dimension on a dial I33, there are nine corresponding punches I80, one for each of the eight off-dimension symbols and a central one for the nominal dimension'symbol. Also, the commutator resistor I11 has a number of insulated segments 58, that is, a central one and four on each side, totaling nine. Between the segments 58 are manually adjustable resistances 60. These control the action of a respective positioning motor I84. This motor through a shaft I86 and a worm gear set I88 controls the rotary position of the respective punch dial 282. Each motor I84 may be of the permanent magnet type. Coupled to each disc I82 is an arm 62 of a rheostat 64.

In order to operate each of the motors I84 so as to turn the corresponding disc I82, each motor I84 and corresponding rheostat 64 are placed in an electronic circuit such as shown in Fig. 22.

Fig. 22 shows schematically one electronic relay circuit whereby an action of a brush I15 on a commutator I11 is accompanied by a follow-up action by a motor I84 to cause in turn a proper setting of a'punoh-setting disc I82. There are eight of these circuits. Referring to said Fig. 22, Whichsliows one of these-circuits, there is shown at numeral NI 9. low voltage transformer fed from the A. C. power line I43. This transformer 20I feeds a bridge circuit shown at the left of Fig. 22, This bridge circuit consists of the commutator I11 on one side and the resistance of the rheostat 64 on the other side. The ends of the commutator I11 and rheostat 64 are connected by wires 204 which are 'fedfr'om the transformer 20I as shown. Brush I15 is electrically connected to arm 62 through the primary of a transformer 206. As has already been described,

.the brush I15 is driven from the dial E33 and the arm 62 is driven from the motor I84. Motor I84 is shown at the right in Fig. 22 and it is to be understood that it controls the position of 62. A dash line has been drawn in Fig. 22 to indicate this fact.

Transformer 206 supplies the input for an amplifier circuit shown at the right which includes a center-tapped secondary of said transformer 206 forming at 208 an adjustable resistance. The latter is connected with the cathodes 2 I of electronic tubes 2I2 and 2I4. These tubes are of the gas-filled type 70L'1-GT. The cathode heaters 2 I6 of these tubes are energized from the line I43 through the transformer 20 I.

A connection 222 feeds current through the adjustable resistance 208 to the cathodes 2I0, the circuit then being traceable to the plates 220 and 224, respectively, of the tubes 2I2 and 2I4. The plate 220 feeds a relay coil 226 and plate 224 feeds a relay coil 228. Coils 226 and 228 are connected to the other side of the line I43 by wires 230. The coils 226 and 228 control an armature 232 which in turn controls a contact 235 of a reversing switch 231 for the reversible motor I84. Condensers 234 damp the pulsating effects of the pulsating direct current flowing through the coils 226 or 228.

When the contactors I15 and 62 are in the same relative positions in the bridge of their members I11 and 64, respectively, no current will flow to the primary of the transformer 206. Hence there will be no output from the secondary of this transformer. However, according to the setting of the rheostat 208, there will be a certain amount of current flowing through the tubes 2I2 and 224 through the coils 226 and 228, respectively, thus holding the contact 235 in the mid position. By adjusting the rheostat 208, the current through the coils 226 and 228 may be made just below the required amount for either coil to draw over the armature 232.

Then if the brush I15 is moved to the right or left, current will flow through the primary of the transformer 206 with a certain polarity. The ends of the secondary of the transformer 206 will assume a corresponding polarity, thus making the grid of one tube more positive and the .grid of the other tube more negative. The grids of the tubes 2I2 and 2M are indexed 239 and 24I, respectively. Thus one tube is blocked and the other increases its feed with respect to its re-v spective one of the coils 226, 228.- This closes the switch 231 in one direction. Thus for an unbalanced condition ofthe bridge circuit due to movement of the brush I15, the current flowing through one of the tubes 2| 2 or 2I4 increases while the other decreases.

Moving the brush I15 to the left, for example, will make the brush I15 positive and the arm 62 negative. Moving the brush I15 to the right will make the brush I15 negative and the arm 62 posi-,

tive. Thus in effect the circuit of Fig. 22 is a polarized relay, the armature 232 closing the contact 235 to the left when brush I15 is moved to the left, and said contact 235 to the right when the brush I15 is moved toward the right. The condenser and resistance combination 243 increases the eifioien-cy of response by properly relating the phase of the input signal applied to the grids 239 and 24L As soon as the brush. H is mo ed in a g v direction, the motor I84 is moved in a direction to cause the arm 62 again to balance the bridge, at which time the contact 235 will reopen to stop the motor. Motor action sets the punch disc I 82 in a proportion corresponding to the amount that the brush I15 has moved. This sets the proper punch I80 with the proper index character over the pan rail 54. The respective index characters correspond to those on the dial I33. To give each properly set punch a blow so that it will register the proper symbol on the pan rail 54, a hammer unit is provided above each punch indexing unit. This hammer unit (Figs. 1'1 and 18) consists of a vertical bearing 245 for a hammer 241, the latter being normally biased up by a spring 249. The upper end of the hammer 241 is in a cylinder 25I which carries a closely fitting movable ball 253, for example 1 in. in diameter. This ball is biased upward by a conical spring 255. The ball 253 is periodically subjected to manually controlled air pressure of approximately 30 p. s. 1. through a port 251. A second ball 259, for example 1 in. in diameter, protrudes into cylinder 25I from the end of a port 26I and is subjected to manually controlled air pressure of approximately 60 p. s. i. in said port 26I. When the 30 p. s. i. pressure is applied in port 251, the total pressure on the ball 253 becomes enough to push it past ball 259. As ball 253 passes the center line of ball 259, the former is quickly accelerated to give a sharp blow to the top of hammer 241. This blow is transmitted to the punch I80, thereby causing the latter to mark the pan rail 54. After air release, the spring 255 returns the ball 253. The control of air pressure in passages 251 and 26I will later be described.

Referring now to Fig. 20, which shows a complete schematic diagram of the apparatus for one set of parts, the remaining elements and operation will now be described. It will be understood that the several additional electrical parts are connected in parallel as required for additional transmitters and recorders but are not shown, for clarity of description.

Each engine block 21 to be tested is placed,

' with pan rails 54 up, on the rollers 22 and between the guides 23. The block is pushed into position against the stop 25 which is in the position shown in the solid lines in Figs. 1, 2 and 5. In Fig. 5 the engine block is not in position but it is in position in Figs. 1 and 2. The fixture 2I upon which the block is thus mounted may be referred to as an inspection table. The placement of the engine block as described makes it possible upon raising the platen I3 to drive the transmitters R axially into the respective cylinders of the block. This is done by admitting fluid from the sump 5 to the cylinder 9 via pipe 263.

Switch A is a momentary-break switch which is normally closed. It is fed from line I43 over wires MI and 303. It is for starting the rise of the platen I3 as will appear. This switch A is connected to the load contacts 309 of a holdingin relay R3 (see wire 305). Relay R3 is normally open. The coil 301 of this relay, in addition to a connection to a source of initial excitation, is connected in series with its own load contact 309. The source of initial excitation for this relay R3 is a normally open limit switch LrWhiCh is carried upon the platen I3 and is operated to close by an upper ring-shaped cam 365. The circuit comprises wire 30I from line wire 335, switch L1, wires 3I I, 3I1, coil 301, wires 3'I5, 3I3 and 3I9, back to wire 331 of power circuit I43. The limit switch L1 is normally open and becomes closed until limit switch L1 causes it to do so.

at the top of the travel of the platen I-3. It reopens on its way down in moving from the cam 365 so that it is again open at the lower end-of its-travel.

A three-way solenoid valve V1, when deenergized by deenergization of relay R3, feeds a regulated air supply to the sump over pipe 323'.

Therefore, when switch A is opened (even temporarily), relay R3 opens and will not reclose As lon as the relay R3 is open, there is no energization of valve V1. This is because V1 obtains its current from relay'Rz via line 3 I I.

An air supply regulator is shown at 201. The

air connection from pipe 323 is above the fluid in the sump 5, which tends to force fluid out from the sump into the cylinder 9 via pipe 293. When the solenoid valve V1 is energized, it shuts off this supply of air pressure and vents the air in the sump 5 to atmosphere, as will appear.

A parallel-connected solenoid condensate valve V3 which is normally open becomes energized to close when relay R2 is energized, being in parallel with V1 across lines 3H and 3I9. This valve V3 closes a condensate vent 34l from the platen I3, or opens this vent when V3 is deenergized. A check valve 269 allows free flow in the direction from the sump 5 to the side of the cylinder 9 but restrict reverse flow. The necessary return-flow restriction is made adjustable. A solenoid valve Vtis normally open, which allows the stated flow.

A three-way solenoid valve V2 becomes energized when relay R3 is energized. The circuit 1, for the purpose from side 335 of the line I43 comprises wire 30I, 303, closed switch A, wire 305, relay R3 when closed, wires 3I'I, 325, 321, 329, solenoid valve V2, wires 33I and 333 to the other side 33'! of the line I 43.

This valve V2 feeds a regulatedsupply of air to the interior of the hollow platen I3 overpipe 32I (see Figs. 2, 3 and This feeds air to all of the transmitter R so as to press their measuring cones II and to spread the feeler balls 8| outward. When deenergized, V2 shuts off this air supply and at 339 vents the air in the transmittersto atmosphere.

The motor I38, which operates the cam I20 as already described, is connected in parallel with the solenoid valve V2 and is fed from the relay R3. It functions only during the downward movement of the platen 13, as will appear.

Thus the operator by temporarily openingthe switch A deenergizes and opens contacts 309 of relay R2, which contacts were closed from aprevious cycle of operation. This deenergizes the solenoid valve Viand causes the feeding ofair pressure to the sump 5. This transfers liquid from the sump 5 to the cylinder 9 via pipe 263 and lifts the platen I3. This drives the trans mitters R up into the'engine cylinders but at this time the transmitters have no air pressure on them and the balls 8| are therefore not pressed into engagement with the cylinders.

When the platen I3 has moved to its top position it stops and then descends, due to the tripping action on cam 3'35 of the limit switch L1. The switch L1 closes at the top of the travel thus energizing R3 to close contacts 309 and energizing V1 to shut the latter and vent it, which allows throttled return flow of fluid from cylinder 9 to sump 5. This allows the transmitters to travel down. Relay R3 has been drawn-shut due to feeding current to its coil over the wires above described.

Switch L1 is thus at this timethe initial source of excitation to energize relay R3. Solenoid valves V1 and V2 shut off the loading air pressures and vent the air in the sump 5 to atmosphere and admit air to the platen I3 and hence to the transmitters R, as explained above. The motor I38, at this time being also energized'by the relay R3, starts to function. The transmitters R now, upon descent, make their measurements of the progressive diameters encountered in the engine cylinders, to indicate such diameters on their respective dials I33, and to show the taper in the cylinders by the spread of the auxiliary right-hand pointers I9I and H3. Left-hand pointers 2H and 2I3 are not used during this part of the cycle.

The rate at which the platen I3 descends is determined by the adjustable orifice check valve 269. As stated, this orifice check valve allows free flow to the cylinder 9 but restricted flow from it, thus restricting the speed of descent of the platen, but not its ascent. As soon as the platen I3 starts the descent, the switch L1 leaves the cam 365 and reopens.

Under the above conditions of descent, the feeler balls BI are pressed out radially against the cylinder walls. V2 is closed. When these balls reach a predetermined point in the engine cylinders, known as the sizing point, the platen is stopped. This sizing point, for example, may be at a point in a cylinder corresponding to the midstroke position of the piston which is later to operate therein. stoppage is automatically effected at the sizing point by tripping of a limit switch L2 which is operated by a lower cam 2' (Figs. 1 and 2). This switch L2 is one of the sources of initial excitation of relay R2. The circuit connecting L2 and R2 is as follows: One side 335 of line I43, wires 30I, 303, normally shut switch A, wire 305, relay contacts 309 (when closed), wires 3I'I, 3I I, 343, normally closed switch B, wire 345, switch L2, wires 341, 349, coil of valve V5, wires 3I3, 3I9 and back to the other side 33! of the line I43. It will be noted that wire 34! also feeds the coil 35I of the relay R2 (see wires 341 and 353). This closes relay R2 and causes valve V5 to remain closed even though the limit switch'L2 reopens.

Normally-open push button switch C is another source of excitation for relay R2. When this switch C is closed, current is fed from side 335 of circuit I43 via wires 30I, 303 to wire 353, coil 35I, wires 3I5, 3I3 and 3I9 and back to wire 33'! of line I43. It will be noted that relay R2, like relay R2, has a holding-in coil. Relay R2 and solenoid valve V5 are normally open. Relay R2 energizes solenoid valve V5, thus shutting off the flow of oil from the cylinder 9 to the sump 5. This stops the downward travel of the platen I3 and of the transmitters R with the balls BI at the sizing point. Thus relay R2 and the solenoid V5 cannot be energized on the upward movement of the platen I3 by the tripping of the limit switch L2, but an operation and holding of push button switch C will at any time stop either upward or downward movement.

It should be understood that the lever II I was 'in the position, during downward travel, as

shown in solid lines in Fig. 4. This had the effect through this non-cooperative position relative to switches L3, L4 and L5 of energizing the coil 201 and applying clutch friction to the pointers I9I and I93. At this time In, which is a single-pole double-throw limit switch, closes one-of its contacts which energizes the coil 355 dotted-line position (Fig. 20).

- the respective dial I33.

13 of a time-delay relay R1, getting its source of power from relay R3. The wiring is as follows: side 335 of line I43, wires 39I, 393, closed switch A, wire 395, closed relay R3, wires 3I'I, 325, 351, 359, switch Lo, coil 355, wire 359 back to side 33'! of line I43. This closes the contacts 36I of relay R1, which by means of wires 393 from line 335 and wire 366 feed the coil 291, the circuit being closed through wires 36'! and 369 to the other side 33! of the line I43. Limit switches L5 and L4 are at this time open. Thus any spread assumed by the pointers will be maintained due to friction at the clutch elements I81, I89 (Fig. 15).

After stopping at the sizing point the operator notes the several diameters of the cylinders at this point and also notes the taper in each cylinder, as indicated by the spread of the auxiliary pointers I9I and I93.

This stenciling operation will be described below.

Or, he may at this time repeat the above cycle of operations but taking diameter measurement in a plane at 90 from the plane of the measurements in the above-described cycle. This is accomplished with the handle II I set at the dotted-line position shown in Fig. 4. When handle III is shifted, bar I99 strikes an operator bar 42 for switches L3, L4 and L5 (Fig. 4). Thus in order to obtain a second series of diameter readings in a plane at 90 from the plane of the first cycle described, the handle III is shifted from the solid-line position shown in Fig. 4 to the dotted-line position, as stated. Push button switch A is again temporarily depressed and opened. The said lifting sequence of the platen I3 above described is then repeated, except that now the auxiliary pointers 2| I and 2 I3 come into play, assuming their respective maximum and minimum positions. This is because the clutch coil 22'! and the coil 65 are at this time energized. The switches L4 and L5 have closed to their dotted-line positions and L3 has moved to its The circuit then reads as follows: starting with the side 335 of the line I43, wires MI, 393, normally closed switch A, wire 395, contacts 399 of relay R3 (when closed), wires 3, 325. 351, closed switch L4, wire 313, coil 221. wire 369 and to the other side 33! of the line I43. A connection 379 from side 335 of the circuit I43 through closed switch L5 feeds coil 63, which is connected to wire 399 passing to the other side 33! of the line I43. Wire 319 also feeds through switch In (now at the dotted-line position) through the coil 355 of the time-delay relay R1, thus holding the contacts of this relay closed. The time delay feature of relay R1 permits shift of handle I II from one position to the other without having the relay R1 fall o en and thus keeps the pointers I9I and I93 maintained in their last positions.

When coil 99 is deenergized, its armature pin 299 is engageable with all of the pointers I9I, I93, 2H and 2I3. When coil 66 is energized, the armature pin 299 clears the pointers I9! and I93, which are left in their last positions, and remains engageable only with the pointers 2H and 2I3. It will be noted that the pointers 2H and 2 I3, when handle I I I is in the solid-line position, do not have their magnetic clutches energized. Therefore they float at zero position with When the handle III is in its dotted-line position, all of the coils291, 22'! and 66 are energized. Thus pointers I9l and I93 remain in their last positions and are not mechanically influenced by the armature pin 299. Under these conditions the pointers 2 I I and 2I3 are mechanically influenced by the armature pin 299 and assume their maximum spread positions due to friction clutching action at 229 and 23I, as caused by energization of coil 22'! (Figs. 15 and 16).

The operator performs a stenciling operation, to be described, based on the diameter at the sizing point. Before performing a stenciling operation he should recognize the taper characteristics because these alone may be grounds for rejecting a given engine block.

After taper observations, as obtained from the pointers I91, I93, 2H and 2I3, coupled with observation of the diameter or diameters at the sizing point, the operator depresses the normally open push button switch D, which energizes the several pneumatic hammers 241 (Fig. 17), one for each cylinder. This stencils the accepted mark on the engine block opposite each cylinder corresponding to the cylinder diameter encountered at the sizing point.

The stenciling operation is accomplished through the actuation by switch D of solenoid valves V6 and V7. The valves Va and V7 are three-way valves which either pass air or vent it. When the switch D is closed, the requisite circuit is closed from side 335 of line I43 via wires 39I closed switch D, wire 38I (closed safety switch 399, to be described below) to valves V6 and V7 in parallel, thence to wire 333 back to the side 33l of the line I93. It will be recalled that each stencil motor is constantly followin the action of the respective brush I15, which is driven in proportion to the action of the respective dial I33. This causes constant repositioning of the stencil discs I82, with the result that a proper stencil I39 is always indexed into stenciling position. When valves V6 and V7 are opened, air is admitted to the two balls 253 and. 259 at the respective pressures of approximately 39 p. s. i. to the ball 253 and 50 p. s. i. to the ball 259. When the pressure above th large ball 253 reaches its full value, the total pressure over the larger area exceeds the total pressure over the smaller ball 259, although the higher unit pressure is applied to the smaller ball 259. Ball 253 then forces back the smaller ball 259 and the former strikes the hammer 24'! below it and thus the respective punch I89 is driven against the pan rail 54. When the push button switch- D is released (opened), the solenoid valves V6 and Vi are deenergized, thus venting the air pressure behind the balls. The ball 253 is instantly returned to its cocked position at the top of the cylinder by its return spring 255.

It will be recalled that now the transmitters R have their balls at the sizing point and it is necessary not only to withdraw these from the engine block but it is also desirable to take continued readings for taper. This will necessitate further descent of the platen I3 to its lowermost position. To do this the operator momentarily pushes the normally closed button switch B. This breaks the circuit which was above described in connection with relay R2 and deenergizes the latter. This in turn deenergizes the coil of valve V5. Fluid then flows from the cylinder 9 to sump 5 via the throttlin check valve 269, and the platen I3 further descends. The pointers I9I, I93 and/or 2, 2I3 continue to be actuated as above described, giving :readings of any, increase in taper, until the end of the cylinder is reached. Finally, the balls 8Iof thetransmitters R enter th master rings 33. This'last action permits the operator to check the zero reference indications for the several transmitters R.

In passing out of the engine cylinders into the table ZI, the balls traverse a small gapwhich in its effect on balls 8| might spoil the'taper readings. This is prevented as follows: By mechanically actuating an interruptor switch 383, the power connection is broken to the inductance bridge measuring circuit. This causes any dial I33 to remain in its last position until the circuit is reconnected. Th detail for this is shown in Fig. 1, wherein a cam 385 contacts the switch arm 381 of switch 383 and forces the switch open, only at the moment when the balls 8| are traversing the gap which is shown at G. The switch 383 is mounted on the underside of the movable platen I3 while the cam lug is mounted ona stationary part of the bed 3. The switch opening needs only to be momentary.

Since it is conceivable that someone might operate the stencil switch D when no engine block is in position and cause damage to the stencils by unnecessarily hammering them, the following safety feature is provided: A switch 389 is placed in wire-38I in series with the switch D. This switch 389 is placed beneath a loose one of the rollers 22, as shown in Figs. 2 and 23. The roller is normally pushed up from the switch by a spring 39 I, but when loaded by means of the engine block the switch 389 will be closed. Thus when the engine block is not in position and the switch 389 opened, the stencil hammers cannot be operated. Both the switches 383 and 389 may be of the micro variety in which very little movement of the operating button is required to open or close them.

From the above it will be seen that by means of the push button starting switch A the transmitters B may be driven upward through the cylinders in the block 27. They may be stopped at will by operating the stop switch C. Action may be resumed at will by pressing the resume switch B. After reaching the top of the stroke they descend automatically. Stenciling is made to occur by pressing the switch D. These switches are suitably marked for the given purposes, as indicated in Fig. 1.

It will also be seen that the starting operation causes an initial lift of the transmitters R without a gaging operation, that is, without air pressure tending to expand the balls 8| into gaging contact with the cylinder walls. When the top of the lift is reached, the downward action starts automatically as stated and at this time the gaging balls 8! are automatically pushed into gaging contact with the cylinder walls for measuring action during the downward travel. Downward action is automatically instigated by the action of switch L1. Operation of the handle or lever II'I allows for a second measuring cycle to be brought about at 90 to the first. Furthermore, during a first cycle taper is indicated by spread between the pointers Fill and I93. During this operation the other pointers 2H and 2I3 follow the dial without spread. Taper during a second measuring cycle (at 90) is indicated by spread of the pointers 2H and 2I3 while the formerly spread pointers I9I and I93 remain apart. During either cycle the dial I33 provides a continual visual indication of the diameters encountered.

7 Finally, the diameter at thesizing point is sym- 'bolized andrecorded on the engine block itself by operation of the stencil switch D.

In view of the above, it will beseen that the several objects of the invention are achieved and other advantageous results attained.

As many changes, could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting-sense.

I claim:

1. A measuring instrument comprising means for predeterminatelypositioning acylinder to be internally measured, a movable-member, a measuring transmitter mountedon the movable member and having pressure-operatedgage members, means for moving the movable member with the transmitter to move the gage members of the latter into the cylinder without pressure on the gage members, means operative automatically at a predetermined position of the movable-member to apply pressure to move said gage members into measuring positions in the cylinder and operative automatically to retract said movable member and the transmitter, means for substantially turning the measuring transmitter relatively to the movable member and the cylinder, means for stopping movement of the movable member and transmitter and for again starting them toward the cylinder in any turned position of the transmitter, and-means for vibrating the transmitter through a limited angle in its turning direction regardless of which of its substantially turned positions it is in.

2. A measuring instrument comprising an inspection table, said table having a master-sized opening therein, means for predeterminately positioning a cylindric member to be internally measured substantially coaxially with respect to the opening, a .movable platen, a measuring transmitter mounted on the platen and having pressure-operated gage .members positioned in said master opening when the platen is in one position, means for moving the platen with the transmitter to move the gage members of the latter from said opening into the cylindric memberwithout pressure onthe gage members, and means operativeautomatically at a predetermined elevation of the platen to apply pressure to move said gage members into measuring positions in the cylinder and automatically to cause retraction of saidplaten and the transmitter.

3. A measuring instrument comprising an inspection table, said table having master-sized openings therein, means for predeterminately positioning a. multi-cylinder member to be internally measured with'its cylinders substantially coaxial with the openings, a movable platen, a plurality of measuring transmitters mounted on the platenand respectively having pressure-operated gage members positioned respectively in said master openings when the platen is in one position, means for movingthe platen with the transmitters to move the gage members of the latter from said master openings into the respective cylinders without pressure on the gage members, and means operative automatically at a predetermined elevation of the platen to apply pressure to move said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters.

4. A measuring instrument comprising an inspection table,-said table having a master-sized Opening therein, means for predeterminately positioning on one side of the table substantially coaxially over the opening a cylindric member to be internally measured, a movable platen on the other side of the table, a measuring transmitter mounted on the platen and having a pressure-operated gage member positioned in said master opening when the platen is in one position, means for moving the platen with the transmitter to move the gage member of the latter from said opening into the cylindric member without pressure on the gage member, means operative automatically at a predetermined advance of the platen toward the table to apply pressure to move said gage member into measuring positions in the cylinder and automatically to cause retraction of said platen and the transmitter, a visual indicator responsive to the action of said age member adapted continuously to indicate diameters met with in the cylinder by said gage member, and visual means adapted to indicate maximum differences in diameters met by the gage member during a given traverse of the gage member in the cylinder.

5. A measuring instrument comprising an inspection table, said table having a master-sized opening therein, means for predeterminately positioning on one side of the table substantially coaxially over the opening a cylindric member to be internally measured, a movable platen on the other side of the table, a measuring transmitter mounted on the platen and having a pressure-operated gage member positioned in said master opening when the platen is in one position, means for moving the platen with the transmitter to move the gage member of the latter from said opening into the cylindric member without pressure on the gage member, means operative automatically at a predetermined advance of the platen toward the table to apply pressure to move said gage ember into measuring positions in the cylinder and automatically to cause retraction of said platen and the transmitter, a visual indicator responsive to the action of said gage member adapted continuously to indicate diameters met with in the cylinder by said gage member, visual means adapted to indicate maximum diiferences in diameters met by the gage member during a given traverse of the gage member in the cylinder, means for rotating the transmitter on the platen for cylinder measurement in a 90 plane and additional visual means adapted to indicate maximum differences in diameters met with by the gage member in said 90 plane but without cancelling the first-named indication of diameter differences.

6. A measuring instrument comprising an inspection table, said table having a master-sized opening therein, means for predeterminately positioning on one side of the table substantially coaxially over the opening a cylindric member to be internally measured, a movable platen on the other side of the table, a measuring transmitter mounted on the platen and having a pressure-operated gage member positioned in said master opening when the platen is in one position, means for moving the platen with the transmitter to move the gage member of the latter from said opening into the cylindric member without pressure on the gage member, means operative automatically at a predetermined advance of the platen toward the table to apply pressure to move said gage member into measuring positions in the cylinder and automatically to cause retraction of said platen and the transmitter, a visual indicator responsive to the action of said gage member adapted continuously to indicate diameters met with in the cylinder by said gage member, visual means adapted to indicate maximum difierences in diameters met by the gage member during a given traverse of the gage member in the cylinder, a turret, a gang of punches thereon respectively indexed accord ing to said visual indicator, circuit means connecting said visual indicator and the turret adapted to cause movement of the turret roportionally to that of the indicator whereby a proper punch to make a mark corresponding to an indication is at any moment indexed into a predetermined marking position, and means for operating any punch that is in indexed position to mark the cylindric member.

7. A measuring instrument comprising an inspection table, said table having a master-sized opening therein, means for predeterminately positioning on one side of the table substantially coaxially over the opening a cylindric member to be internally measured, a movable platen on the other side of the table, a measuring transmitter mounted on the platen and having a pressure-operated gage member positioned in said master opening when the platen is in one position, means for moving the platen with the transmitter to move the gage member of latter from said opening into the cylindric member without pressure on the gage member, means operative automatically at a predetermined advance of the platen toward the table to apply pressure to move said gage member into measuring positions in the cylinder and automatically to cause retraction of said platen and the transmitter, a visual indicator responsive to the action of said gage member adapted continuously to indicate diameters met with in the cylinder by said gage member, visual means adapted to indicate maximum differences in diameters met by the gage member during a given traverse of the .gage member in the cylinder, means for rotating the transmitter on the platen for cylinder measurement in a plane, additional visual means adapted to indicate maximum differences in diameter, met with by the gage member in said 90 plane but without cancelling the first-named indication of diameter differences, a turret, a gang of punches thereon respectively indexed according to said visual indicator, circuit means connecting said visual indicator and the turret adapted to cause movement of the turret proportionally to that of the indicator whereby a proper punch to make a mark corresponding to an indication is at any moment indexed into a predetermined marking position, and means for operating any punch that is in indexed position to mark the cylindric member.

8. A measuring instrument comprising an inspection table, said table having a series of master-sized openings therein, means for predeterminately positioning a multi-cylinder member to be internally measured with its cylinders respectively substantially coaxial over the respective openings, a movable platen, elongate measurement transmitters mounted on the platen and having pressure-operated gage members respectively positioned in said master openings when the platen is in a retracted position, one means for advancing the platen with all of the transmitters simultaneously to move the gage members of the latter from said openings into the cylinders without pressure on the gage meme 19 bers, means operative automatically at a predetermined advance of the platen to apply pressure to move all of said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters, individual indicators responsive respectively to the respective actions of said gage members in the cylinders and being each adapted continuously to indicate an individual diameter met with in a cylinder by one of said gage members, and individual visual means adapted to indicate maximum differences in diameters respectively met with by the gage members during a given traverse of the respective gage member in a cylinder.

9. A measuring instrument comprising an inspection table, said table having a series of master-sized openings therein, means for predeterminately positioning a multi-cylinder member to be internally measured with its cylinders respectively substantially coaxial over the respective openings, a movable platen, elongate measurement transmitters mounted on the platen and having pressure-operated gage members respectively positioned in said master openings when the platen is in a retracted position, one means for advancing the platen with all of the transmitters simultaneously to move the gage members of the latter from said openings into the cylinders without pressure on the gage members, means operative automatically at a predetermined advance of the platen to apply pressure to move all of said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters, in-

dividual indicators responsive respectively to the respective actions of said gage members in the cylinders and being each adapted continuously to indicate an individual diameter met with in a cylinder by one of said gage members, individual visual means adapted to indicate maximum difierences in diameters respectively met with by the gage members during a given traverse of the respective gage member in a cylinder, and common means for rotating all transmitters on the platen to 90 positions.

10. A measuring instrument comprising an inspection table, said table having a series of master-sized openings therein, means for predeterminately positioning a multi-cylinder member to be internally measured with its cylinders respectively substantially coaxial over the respective openings, a movable platen, elongate measurement transmitters mounted on the platen and having pressure-operated gage members respectively positioned in said master openings when the platen is in a retracted position, one means for advancing the platen with all of the transmitters simultaneously to move the gage members of the latter from said openings into the cylinders without pressure on the gage members, means operative automatically at a predetermined advance of the platen to apply pressure to move all of said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters, individual indicators responsive respectively to the respective actions of said gage members in the cylinders and being each adapted continuously to indicate an individual diameter met with in a cylinder by one of said gage members, individual visual means adapted to indicate maximum differences in diameters respectively met with by the gage members during a given traverse of the respective gage member in a cylinder, common means for rotating all transdifferences.

20 mitters on the platen for vibrating said common rotating means less than in either 90 position.

11. A measuring instrument comprising an' inspection table, said table having a series of master-sized openings therein, means for predeterminately positioning a multi-cylinder member to be internally measured with its cylinders respectively substantially coaxial over the respective openings, a movable platen, elongate measurement transmitters mounted on the platen and having pressure-operated gage members respectively positioned in said master openings When the platen is in a retracted position, one means for advancing the platen with all of the transmitters simultaneously to move the gage members of the latter from said openings into the cylinders without pressure on the gage members, means operative automatically at a predetermined advance of the platen to apply pressure to move all of said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters, individual indicators responsive respectively to the respective actions of said gage members in the cylinders and being each adapted continuously to indicate an individual diameter met with in a cylinder by one of said gage members, individual visual means adapted to indicate maximum differences in diameters respectively met with by the gage members during a given traverse of the respective gage member in a cylinder, common means for rotating all transmitters on the platen to 90 positions, and additional individual indicating means adapted to indicate maximum differences in diameters respectively met with by the gage members in another traverse when the transmitters are rotated 90, without cancelling the indications of the first mentioned indications of maximum 12. A measuring instrument comprising an inspection table, said table having a series of master-sized openings therein, means for predeterminately positioning a multi-cylinder member to be internally measured with its cylinders respectively substantially coaxial over the respective openings, a movable platen, elongate measurement transmitters mounted on the platen and having pressure-operated gage members respectively positioned in said master openings when the platen' is in a retracted position, one means foradvancing the platen with all of the transmitters simultaneously to move the gage members of the latter from said openings into the cylinders without pressure on the gage members, means operative automatically at a predetermined advance of the platen to apply pressure to move all of said gage members into measuring positions in the cylinders and to cause retraction of said platen and the transmitters, individual indicators responsive respectively to the respective actions of said gage members in the cylinders and being each adapted continuously 'to indicate an individual diameter met with in a cylinder by one of said gage members, individual visual means adapted to indicate maximum differences in diameters respectively met with by the gage members during a given traverse of the respective gage member in a cylinder, common means for rotating all transmitters on the platen to 90 positions, additional individual indicating means adapted to indicate maximum differences in diameters respectively met with by the gage members in another traverse when to 90 positions, and means" 

